Researchers from University of Copenhagen followed 60 heavy and healthy men for 13 weeks and reported that people who had a daily exercise of 30 minutes lost weight as much as those who had a 60-minute exercise.
In the study, half of the participants were assigned to exercise for one hour a day, wearing a heart-rate monitor and calorie counter. The remaining half was asked to exercise 30 minutes a day. It was found that people who exercised for 30 minutes a day was enough to lose weight.
The findings showed that participants who exercised 30 minutes a day lost 3.6 kilos in 3 months. In comparison, those who exercised for an hour a day only lost 2.7 kilos. The reduction in body mass, however, was about 4 kilos for both groups.
One possible explanation provided by the researchers is that participants found half an hour of exercise achievable for them and they had the desire and energy for more physical activity after their daily exercise session. It is also possible that the participants who exercised for 60 minutes a day ate more so they lost weight slightly less than anticipated.
The findings, however, have some limitations. The study involved only young men, whose metabolisms and weight-loss motivations might differ significantly from those of other age groups and women. Meanwhile, the study duration was rather short. It is likely that the results might change if the period of continued exercise is longer.